x11-base/xorg-server: backport BadIDChoice fix w/ MaxClients

I was hoping this would slip into a release but it hasn't yet.

In any case, this fix has been on master for a while & I've
been running with it for months.

Closes: https://bugs.gentoo.org/857483
Closes: https://bugs.gentoo.org/875977
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/x11-base/xorg-server/files/xorg-server-21.1.4-BadIDChoice.patch b/x11-base/xorg-server/files/xorg-server-21.1.4-BadIDChoice.patch
new file mode 100644
index 000000000000..def3c58714b4
--- /dev/null
+++ b/x11-base/xorg-server/files/xorg-server-21.1.4-BadIDChoice.patch
@@ -0,0 +1,59 @@
+https://bugs.gentoo.org/857483
+https://gitlab.freedesktop.org/xorg/xserver/-/issues/1310
+https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/953
+
+From f61307631203ab0266c035db07c2f776cf7c6cf4 Mon Sep 17 00:00:00 2001
+From: Olivier Fourdan <ofourdan@redhat.com>
+Date: Tue, 12 Jul 2022 14:44:48 +0200
+Subject: [PATCH] dix: Fix overzealous caching of ResourceClientBits()
+
+Commit c7311654 cached the value of ResourceClientBits(), but that value
+depends on the `MaxClients` value set either from the command line or
+from the configuration file.
+
+For the latter, a call to ResourceClientBits() is issued before the
+configuration file is read, meaning that the cached value is from the
+default, not from the maximum number of clients set in the configuration
+file.
+
+That obviously causes all sort of issues, including memory corruption
+and crashes of the Xserver when reaching the default limit value.
+
+To avoid that issue, also keep the LimitClient value, and recompute the
+ilog2() value if that changes, as on startup when the value is set from
+the the xorg.conf ServerFlags section.
+
+v2: Drop the `cache == 0` test
+    Rename cache vars
+
+Fixes: c7311654 - dix: cache ResourceClientBits() value
+Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1310
+Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
+Reviewed-by: Adam Jackson <ajax@redhat.com>
+(cherry picked from commit 2efa6d659508346358a1ef27b2393e18843f66a3)
+--- a/dix/resource.c
++++ b/dix/resource.c
+@@ -620,12 +620,15 @@ ilog2(int val)
+ unsigned int
+ ResourceClientBits(void)
+ {
+-    static unsigned int cached = 0;
++    static unsigned int cache_ilog2 = 0;
++    static unsigned int cache_limit = 0;
+ 
+-    if (cached == 0)
+-      cached = ilog2(LimitClients);
++    if (LimitClients != cache_limit) {
++        cache_limit = LimitClients;
++        cache_ilog2 = ilog2(LimitClients);
++    }
+ 
+-    return cached;
++    return cache_ilog2;
+ }
+ 
+ /*****************
+-- 
+GitLab
+
+